Mike Conway stormed to the top of the timesheets during Saturday afternoon's test session at the FIA World Endurance Championship Prologue.
The Toyota TS050 driver posted a best time of 1:31.332s to gain seven tenths of a second clearance at the head of the LMP1 order.
Second quickest during the three-hour afternoon run was Kazuki Nakajima in the sister TS050 with a 1:32.062.
Both Toyota times were enough to nudge the morning benchmark set by Neel Jani in the #1 Porsche 919 Hybrid.
Brendon Hartley finished third in the times on board the #2 Porsche with a 1:32.146s effort.
WEC Monza Prologue session 2 result
The session was red flagged with just over an hour to go when Kevin Estre beached his GTE-Pro class Porsche 911 RSR at the second chicane.
Prior to that the Frenchman had set the fastest time in category, and despite the spin was able to hold on to the top spot with a time of 1:47.844s.
The #24 Manor/CEFC ORECA 07-Gibson also encountered trouble, bringing out the yellow flags at the same location following a trip into the gravel.
LMP2 was led by reigning class champion Gustavo Menezes (Signatech Alpine), while Gulf Racing paced GTE-Am for the second session in a row.
The only night session of the WEC Prologue is set to get underway at 19:00 local time on Saturday evening.